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Kazaz S, Billeter E, Longo F, Borgschulte A, Łodziana Z. Why Hydrogen Dissociation Catalysts do not Work for Hydrogenation of Magnesium. Adv Sci (Weinh) 2024; 11:e2304603. [PMID: 38070182 PMCID: PMC10870026 DOI: 10.1002/advs.202304603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/13/2023] [Indexed: 02/17/2024]
Abstract
Provision of atomic hydrogen by hydrogen dissociation catalysts only moderately accelerates the hydrogenation rate of magnesium. They shed light on this well-known but technically challenging fact through a combined approach using an unconventional surface science technique together with Density Functional Theory (DFT) calculations. The calculations demonstrate the drastic electronic structure changes during transformation of Mg to MgH2 , which make fractional hydrogen coverage on the surface, as well as substoichiometric hydrogen content in the bulk energetically unfavorable. Reflecting Electron Energy Loss Spectroscopy (REELS) is used to measure the surface and bulk plasmon during hydrogen sorption in magnesium. The measurements show that the hydrogenation proceeds via the growth of magnesium hydride without the presence of chemisorbed hydrogen on the metallic magnesium surface exactly as indicated by the calculations. This is due to the low stability of sub-stoichiometric amounts of chemisorbed H correlating with the unfavorable charge state of Mg. They are merely bound to the unchanged adjacent Mg layers, thereby explaining the failure of classical hydrogenation catalysts, which effectively only hydrogenate Mg in their direct vicinity. The acceleration of hydrogen sorption kinetics in Mg must affect the polarization in the interface between Mg and MgH2 during hydrogenation.
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Affiliation(s)
- Selim Kazaz
- Laboratory for Advanced Analytical TechnologiesSwiss Federal Laboratories for Materials Science and Technology EmpaÜberlandstrasse 129DübendorfCH‐8600Switzerland
- Department of ChemistryUniversity of ZurichWinterthurerstrasse 190ZürichCH‐8057Switzerland
| | - Emanuel Billeter
- Laboratory for Advanced Analytical TechnologiesSwiss Federal Laboratories for Materials Science and Technology EmpaÜberlandstrasse 129DübendorfCH‐8600Switzerland
- Department of ChemistryUniversity of ZurichWinterthurerstrasse 190ZürichCH‐8057Switzerland
| | - Filippo Longo
- Laboratory for Advanced Analytical TechnologiesSwiss Federal Laboratories for Materials Science and Technology EmpaÜberlandstrasse 129DübendorfCH‐8600Switzerland
- Department of ChemistryUniversity of ZurichWinterthurerstrasse 190ZürichCH‐8057Switzerland
| | - Andreas Borgschulte
- Laboratory for Advanced Analytical TechnologiesSwiss Federal Laboratories for Materials Science and Technology EmpaÜberlandstrasse 129DübendorfCH‐8600Switzerland
- Department of ChemistryUniversity of ZurichWinterthurerstrasse 190ZürichCH‐8057Switzerland
| | - Zbigniew Łodziana
- Institute of Nuclear PhysicsPolish Academy of SciencesKrakowPL‐31342Poland
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2
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De Fanis A, Ilchen M, Achner A, Baumann TM, Boll R, Buck J, Danilevsky C, Esenov S, Erk B, Grychtol P, Hartmann G, Liu J, Mazza T, Montaño J, Music V, Ovcharenko Y, Rennhack N, Rivas D, Rolles D, Schmidt P, Sotoudi Namin H, Scholz F, Viefhaus J, Walter P, Ziółkowski P, Zhang H, Meyer M. High-resolution electron time-of-flight spectrometers for angle-resolved measurements at the SQS Instrument at the European XFEL. J Synchrotron Radiat 2022; 29:755-764. [PMID: 35511008 PMCID: PMC9070712 DOI: 10.1107/s1600577522002284] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 02/26/2022] [Indexed: 06/14/2023]
Abstract
A set of electron time-of-flight spectrometers for high-resolution angle-resolved spectroscopy was developed for the Small Quantum Systems (SQS) instrument at the SASE3 soft X-ray branch of the European XFEL. The resolving power of this spectrometer design is demonstrated to exceed 10 000 (E/ΔE), using the well known Ne 1s-13p resonant Auger spectrum measured at a photon energy of 867.11 eV at a third-generation synchrotron radiation source. At the European XFEL, a width of ∼0.5 eV full width at half-maximum for a kinetic energy of 800 eV was demonstrated. It is expected that this linewidth can be reached over a broad range of kinetic energies. An array of these spectrometers, with different angular orientations, is tailored for the Atomic-like Quantum Systems endstation for high-resolution angle-resolved spectroscopy of gaseous samples.
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Affiliation(s)
| | - Markus Ilchen
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | | | | | - Rebecca Boll
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Jens Buck
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | | | - Sergey Esenov
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Benjamin Erk
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | | | - Gregor Hartmann
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Jia Liu
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Tommaso Mazza
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | | | - Valerija Music
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | | | - Nils Rennhack
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Daniel Rivas
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Daniel Rolles
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS, USA
| | - Philipp Schmidt
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | | | - Frank Scholz
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Jens Viefhaus
- Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Peter Walter
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | | | - Haiou Zhang
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Michael Meyer
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
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3
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Surnev S, Netzer FP. Tungsten and molybdenum oxide nanostructures: two-dimensional layers and nanoclusters. J Phys Condens Matter 2022; 34:233001. [PMID: 35045403 DOI: 10.1088/1361-648x/ac4ceb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
W- and Mo-oxides form an interesting class of materials, featuring structural complexities, stoichiometric flexibility, and versatile physical and chemical properties that render them attractive for many applications in diverse fields of nanotechnologies. In nanostructured form, novel properties and functionalities emerge as a result of quantum size and confinement effects. In this topical review, W- and Mo-oxide nanosystems are examined with particular emphasis on two-dimensional (2D) layers and small molecular-type clusters. We focus on the epitaxial growth of 2D layers on metal single crystal surfaces and investigate their novel geometries and structures by a surface science approach. The coupling between the oxide overlayer and the metal substrate surface is a decisive element in the formation of the oxide structures and interfacial strain and charge transfer are shown to determine the lowest energy structures. Atomic structure models as determined by density functional theory (DFT) simulations are reported and discussed for various interface situations, with strong and weak coupling. Free-standing (quasi-)2D oxide layers, so-called oxide nanosheets, are attracting a growing interest recently in the applied research community because of their easy synthesis via wet-chemical routes. Although they consist typically of several atomic layers thick-not always homogeneous-platelet systems, their quasi-2D character induces a number of features that make them attractive for optoelectronic, sensor or biotechnological device applications. A brief account of recently published preparation procedures of W- and Mo-oxide nanosheets and some prototypical examples of proof of concept applications are reported here. (MO3)3(M = W, Mo) clusters can be generated in the gas phase in nearly monodisperse form by a simple vacuum sublimation technique. These clusters, interesting molecular-type structures by their own account, can be deposited on a solid surface in a controlled way and be condensed into 2D W- and Mo-oxide layers; solid-state chemical reactions with pre-deposited surface oxide layers to form 2D ternary oxide compounds (tungstates, molybdates) have also been reported. The clusters have been proposed as model systems for molecular studies of reactive centres in catalytic reactions. Studies of the catalysis of (MO3)3clusters in unsupported and supported forms, using the conversion of alcohols as model reactions, are discussed. Finally, we close with a brief outlook of future perspectives.
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Affiliation(s)
- Svetlozar Surnev
- Surface and Interface Physics, Institute of Physics, Karl-Franzens University Graz, A-8010 GRAZ, Austria
| | - Falko P Netzer
- Surface and Interface Physics, Institute of Physics, Karl-Franzens University Graz, A-8010 GRAZ, Austria
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4
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Mirzehmet A, Ohtsuka T, Abd Rahman SA, Yuyama T, Krüger P, Yoshida H. Surface Termination of Solution-Processed CH 3NH 3PbI 3 Perovskite Film Examined using Electron Spectroscopies. Adv Mater 2021; 33:e2004981. [PMID: 33617084 DOI: 10.1002/adma.202004981] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/19/2020] [Indexed: 05/21/2023]
Abstract
The interfaces of a perovskite solar cell significantly influence the charge processes in the cell, which contributes to the device performance with direct implication for surface potential, electronic structure, and chemical reactivity. The properties of the interface are strongly affected by the surface termination. In this work, the combination of ultraviolet photoelectron spectroscopy (UPS) and metastable-atom electron spectroscopy is demonstrated, to examine the surface termination of a solution-processed CH3NH3PbI3 perovskite film. The results show that the surface of the CH3NH3PbI3 perovskite film is terminated with a layer consisting of CH3NH3 and I. The interface energy level alignment for both occupied and unoccupied levels between CH3NH3PbI3 and C60 is also examined using UPS and low-energy inverse photoelectron spectroscopy. It turns out that an ideal energy level alignment is established for the electron collection and hole block at the perovskite and C60 interface.
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Affiliation(s)
- Abduheber Mirzehmet
- Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Tomoki Ohtsuka
- Graduate School of Science and Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Syed A Abd Rahman
- Graduate School of Science and Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Tomoki Yuyama
- Graduate School of Science and Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Peter Krüger
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
- Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Hiroyuki Yoshida
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
- Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
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5
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Harvey TR, Henke JW, Kfir O, Lourenço-Martins H, Feist A, García de Abajo FJ, Ropers C. Probing Chirality with Inelastic Electron-Light Scattering. Nano Lett 2020; 20:4377-4383. [PMID: 32383890 DOI: 10.1021/acs.nanolett.0c01130] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Circular dichroism spectroscopy is an essential technique for understanding molecular structure and magnetic materials; however, spatial resolution is limited by the wavelength of light, and sensitivity sufficient for single-molecule spectroscopy is challenging. We demonstrate that electrons can efficiently measure the interaction between circularly polarized light and chiral materials with deeply subwavelength resolution. By scanning a nanometer-sized focused electron beam across an optically excited chiral nanostructure and measuring the electron energy spectrum at each probe position, we produce a high-spatial-resolution map of near-field dichroism. This technique offers a nanoscale view of a fundamental symmetry and could be employed as "photon staining" to increase biomolecular material contrast in electron microscopy.
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Affiliation(s)
- Tyler R Harvey
- Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - Jan-Wilke Henke
- Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - Ofer Kfir
- Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | | | - Armin Feist
- Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Claus Ropers
- Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
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6
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Hettler S, Sreedhara MB, Serra M, Sinha SS, Popovitz-Biro R, Pinkas I, Enyashin AN, Tenne R, Arenal R. YS-TaS 2 and Y xLa 1-xS-TaS 2 (0 ≤ x ≤ 1) Nanotubes: A Family of Misfit Layered Compounds. ACS Nano 2020; 14:5445-5458. [PMID: 32347713 PMCID: PMC7467812 DOI: 10.1021/acsnano.9b09284] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 04/29/2020] [Indexed: 05/23/2023]
Abstract
We present the analysis of a family of nanotubes (NTs) based on the quaternary misfit layered compound (MLC) YxLa1-xS-TaS2. The NTs were successfully synthesized within the whole range of possible compositions via the chemical vapor transport technique. In-depth analysis of the NTs using electron microscopy and spectroscopy proves the in-phase (partial) substitution of La by Y in the (La,Y)S subsystem and reveals structural changes compared to the previously reported LaS-TaS2 MLC-NTs. The observed structure can be linked to the slightly different lattice parameters of LaS and YS. Raman spectroscopy and infrared transmission measurements reveal the tunability of the plasmonic and vibrational properties. Density-functional theory calculations showed that the YxLa1-xS-TaS2 MLCs are stable in all compositions. Moreover, the calculations indicated that substitution of La by Sc atoms is electronically not favorable, which explains our failed attempt to synthesize these MLC and NTs thereof.
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Affiliation(s)
- Simon Hettler
- Instituto
de Nanociencia de Aragón, Universidad
de Zaragoza, 50018 Zaragoza, Spain
| | - M. B. Sreedhara
- Department of Materials and Interfaces and Department of
Chemical Research
Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Marco Serra
- Department of Materials and Interfaces and Department of
Chemical Research
Support, Weizmann Institute of Science, Rehovot 76100, Israel
- Department
of Physical Chemistry, Center for Biomedical Research (CINBIO), Universidad de Vigo, 36310 Vigo, Spain
| | - Sudarson S. Sinha
- Department of Materials and Interfaces and Department of
Chemical Research
Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ronit Popovitz-Biro
- Department of Materials and Interfaces and Department of
Chemical Research
Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Iddo Pinkas
- Department of Materials and Interfaces and Department of
Chemical Research
Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Andrey N. Enyashin
- Institute
of Solid State Chemistry UB RAS, 620990 Ekaterinburg, Russian Federation
- Institute
of Natural Sciences and Mathematics, Ural
Federal University, 620083 Ekaterinburg, Russian Federation
| | - Reshef Tenne
- Department of Materials and Interfaces and Department of
Chemical Research
Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Raul Arenal
- Instituto
de Nanociencia de Aragón, Universidad
de Zaragoza, 50018 Zaragoza, Spain
- Instituto
de Ciencias de Materiales Aragón, CSIC-U. Zaragoza, 50009 Zaragoza, Spain
- ARAID
Foundation, 50018 Zaragoza, Spain
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7
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Falcinelli S, Pirani F, Candori P, Brunetti BG, Farrar JM, Vecchiocattivi F. A New Insight on Stereo-Dynamics of Penning Ionization Reactions. Front Chem 2019; 7:445. [PMID: 31275926 PMCID: PMC6591474 DOI: 10.3389/fchem.2019.00445] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/31/2019] [Indexed: 12/25/2022] Open
Abstract
Recent developments in the experimental study of Penning ionization reactions are presented here to cast light on basic aspects of the stereo-dynamics of the microscopic mechanisms involved. They concern the dependence of the reaction probability on the relative orientation of the atomic and molecular orbitals of reagents and products. The focus is on collisions between metastable Ne*(3P2, 0) atoms with other noble gas atoms or molecules, for which play a crucial role both the inner open-shell structure of Ne* and the HOMO orbitals of the partner. Their mutual orientation with respect to the intermolecular axis controls the characteristics of the intermolecular potential, which drives the collision dynamics and the reaction probability. The investigation of ionization processes of water, the prototype of hydrogenated molecules, suggested that the ground state of water ion is produced when Ne* approaches H2O perpendicularly to its plane. Conversely, collisions addressed toward the lone pair, aligned along the water C2v symmetry axis, generates electronically excited water ions. However, obtained results refer to a statistical/random orientation of the open shell ionic core of Ne*. Recently, the attention focused on the ionization of Kr or Xe by Ne*, for which we have been able to characterize the dependence on the collision energy of the branching ratio between probabilities of spin orbit resolved elementary processes. The combined analysis of measured PIES spectra suggested the occurrence of contributions from four different reaction channels, assigned to two distinct spin-orbit states of the Ne*(3P2, 0) reagent and two different spin-orbit states of the ionic M+(2P3/2, 1/2) products (M = Kr, Xe). The obtained results emphasized the reactivity change of 3P0 atoms with respect to 3P2, in producing ions in 2P3/2 and 2P1/2 sublevels, as a function of the collision energy. These findings have been assumed to arise from a critical balance of adiabatic and non-adiabatic effects that control formation and electronic rearrangement of the collision complex, respectively. From these results we are able to characterize for the first time, according to our knowledge, the state to state reaction probability for the ionization of Kr and Xe by Ne* in both 3P2 and 3P0 sublevels.
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Affiliation(s)
- Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | - Fernando Pirani
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Pietro Candori
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | - Brunetto G Brunetti
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - James M Farrar
- Department of Chemistry, University of Rochester, Rochester, NY, United States
| | - Franco Vecchiocattivi
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
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8
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Yin Y, Lewis DA, Andersson GG. Influence of Moisture on the Energy-Level Alignment at the MoO 3/Organic Interfaces. ACS Appl Mater Interfaces 2018; 10:44163-44172. [PMID: 30465425 DOI: 10.1021/acsami.8b16725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
MoO3 is widely used in polymer-based organic solar cells as an anode buffer layer because of its high workfunction and formation of a strong dipole at the MoO3/polymer interface facilitating charge transfer across the MoO3/polymer interface. In the present work, we show that exposure of the MoO3/polymer interface to moisture attracts water molecules to the interface via diffusion. Because of their own strong dipole, water molecules counter the dipole at the MoO3/polymer interface. As a consequence, the charge transfer across the MoO3/polymer will reduce and affect the charge transport across the interface. The outcome of this work thus suggests that it is critical to keep the MoO3/polymer interface moisture-free, which requires special precautions in device fabrications. The composition of the MoO3/P3HT:PC61BM interface is analyzed with X-ray photoelectron spectroscopy and the depth profiling technique, neutral impact collision ion scattering spectroscopy. The results show that the concentration of oxygen increases upon exposure but leaves the oxidation state of Mo unchanged. The valence electron spectroscopy technique shows that the dipole across the MoO3/P3HT:PC61BM interface decreases even for short-time exposure to atmosphere because of the diffusion of water molecules to the interface. The far-ranging consequences for organic electronic devices are discussed.
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Affiliation(s)
- Yanting Yin
- Flinders Institute for Nanoscale Science and Technology , Flinders University , GPO Box 2100, Adelaide SA 5001 , Australia
| | - David A Lewis
- Flinders Institute for Nanoscale Science and Technology , Flinders University , GPO Box 2100, Adelaide SA 5001 , Australia
| | - Gunther G Andersson
- Flinders Institute for Nanoscale Science and Technology , Flinders University , GPO Box 2100, Adelaide SA 5001 , Australia
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9
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Chambers BA, Shearer CJ, Yu L, Gibson CT, Andersson GG. Measuring the Density of States of the Inner and Outer Wall of Double-Walled Carbon Nanotubes. Nanomaterials (Basel) 2018; 8:nano8060448. [PMID: 29921819 PMCID: PMC6027179 DOI: 10.3390/nano8060448] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 06/07/2018] [Accepted: 06/14/2018] [Indexed: 11/27/2022]
Abstract
The combination of ultraviolet photoelectron spectroscopy and metastable helium induced electron spectroscopy is used to determine the density of states of the inner and outer coaxial carbon nanotubes. Ultraviolet photoelectron spectroscopy typically measures the density of states across the entire carbon nanotube, while metastable helium induced electron spectroscopy measures the density of states of the outermost layer alone. The use of double-walled carbon nanotubes in electronic devices allows for the outer wall to be functionalised whilst the inner wall remains defect free and the density of states is kept intact for electron transport. Separating the information of the inner and outer walls enables development of double-walled carbon nanotubes to be independent, such that the charge transport of the inner wall is maintained and confirmed whilst the outer wall is modified for functional purposes.
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Affiliation(s)
- Benjamin A Chambers
- Flinders Centre for NanoScale Science and Technology, Flinders University, Adelaide SA 5001, Australia.
| | - Cameron J Shearer
- Flinders Centre for NanoScale Science and Technology, Flinders University, Adelaide SA 5001, Australia.
- Department of Chemistry, The University of Adelaide, Adelaide SA 5005, Australia.
| | - LePing Yu
- Flinders Centre for NanoScale Science and Technology, Flinders University, Adelaide SA 5001, Australia.
| | - Christopher T Gibson
- Flinders Centre for NanoScale Science and Technology, Flinders University, Adelaide SA 5001, Australia.
| | - Gunther G Andersson
- Flinders Centre for NanoScale Science and Technology, Flinders University, Adelaide SA 5001, Australia.
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10
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Hassan MT, Bateman F, Collett B, Darius G, DeAngelis C, Dewey MS, Jones GL, Komives A, Laptev A, Mendenhall MP, Nico JS, Noid G, Stephenson EJ, Stern I, Trull C, Wietfeldt FE. The aCORN Backscatter-Suppressed Beta Spectrometer. Nucl Instrum Methods Phys Res A 2017; 867:10.1016/j.nima.2017.05.029. [PMID: 31092963 PMCID: PMC6512858 DOI: 10.1016/j.nima.2017.05.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Backscatter of electrons from a beta spectrometer, with incomplete energy deposition, can lead to undesirable effects in many types of experiments. We present and discuss the design and operation of a backscatter-suppressed beta spectrometer that was developed as part of a program to measure the electronantineutrino correlation coefficient in neutron beta decay (aCORN). An array of backscatter veto detectors surrounds a plastic scintillator beta energy detector. The spectrometer contains an axial magnetic field gradient, so electrons are efficiently admitted but have a low probability for escaping back through the entrance after backscattering. The design, construction, calibration, and performance of the spectrometer are discussed.
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Affiliation(s)
- M T Hassan
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118, USA
| | - F Bateman
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - B Collett
- Physics Department, Hamilton College, Clinton, NY 13323, USA
| | - G Darius
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118, USA
| | - C DeAngelis
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118, USA
| | - M S Dewey
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - G L Jones
- Physics Department, Hamilton College, Clinton, NY 13323, USA
| | - A Komives
- Department of Physics and Astronomy, DePauw University, Greencastle, IN 46135, USA
| | - A Laptev
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118, USA
| | - M P Mendenhall
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J S Nico
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - G Noid
- CEEM, Indiana University, Bloomington, IN 47408, USA
| | | | - I Stern
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118, USA
| | - C Trull
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118, USA
| | - F E Wietfeldt
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118, USA
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Bourke JD, Chantler CT. Momentum-Dependent Lifetime Broadening of Electron Energy Loss Spectra: A Self-Consistent Coupled-Plasmon Model. J Phys Chem Lett 2015; 6:314-9. [PMID: 26261939 DOI: 10.1021/jz5023812] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The complex dielectric function and associated energy loss spectrum of a condensed matter system is a fundamental material parameter that determines both the optical and electronic scattering behavior of the medium. The common representation of the electron energy loss function (ELF) is interpreted as the susceptibility of a system to a single- or bulk-electron (plasmon) excitation at a given energy and momentum and is commonly derived as a summation of noninteracting free-electron resonances with forms constrained by adherence to some externally determined optical standard. This work introduces a new causally constrained momentum-dependent broadening theory, permitting a more physical representation of optical and electronic resonances that agrees more closely with both optical attenuation and electron scattering data. We demonstrate how the momentum dependence of excitation resonances may be constrained uniquely by utilizing a coupled-plasmon model, in which high-energy excitations are able to relax into lower-energy excitations within the medium. This enables a robust and fully self-consistent theory with no free or fitted parameters that reveals additional physical insight not present in previous work. The new developments are applied to the scattering behavior of solid molybdenum and aluminum. We find that plasmon and single-electron lifetimes are significantly affected by the presence of alternate excitation channels and show for molybdenum that agreement with high-precision electron inelastic mean free path data is dramatically improved for energies above 20 eV.
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Affiliation(s)
- J D Bourke
- School of Physics, University of Melbourne, Parkville, Victoria 3010 Australia
| | - C T Chantler
- School of Physics, University of Melbourne, Parkville, Victoria 3010 Australia
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Miron C, Patanen M. Synchrotron-radiation-based soft X-ray electron spectroscopy applied to structural and chemical characterization of isolated species, from molecules to nanoparticles. Adv Mater 2014; 26:7911-7916. [PMID: 24902675 DOI: 10.1002/adma.201304837] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 01/27/2014] [Indexed: 06/03/2023]
Abstract
With its extended tunability from the IR to hard X-rays and the exceptional spectral brightness offered by the 3rd generation storage rings, synchrotron radiation (SR) is an invaluable investigation tool. Major methodological developments are now available, and are applied to simple, isolated atoms and molecules (which can be often modeled ab initio) and are then extended to the investigation of more and more complex species, up to soft and hard condensed matter. The present article highlights, with a few examples, the most recent achievements in SR-based soft X-ray electron spectroscopy applied to the structural characterization of isolated species of increasing complexity, from molecules and clusters to nanoparticles. Special attention is devoted to very high resolution studies of single molecules revealing electron diffraction and interference effects, as well as detailed information about their potential energy surfaces. These achievements are only possible based on the new opportunities offered by the most advanced SR facilities.
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Affiliation(s)
- Catalin Miron
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192, Gif-sur-Yvette Cedex, France
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Komives A, Wietfeldt FE, Trull C, Bateman FB, Dewey MS, Thompson AK, Anderman R, Balashov S, Mostovoy Y. A Backscatter Suppressed Electron Detector for the Measurement of "a". J Res Natl Inst Stand Technol 2005; 110:431-436. [PMID: 27308163 PMCID: PMC4852833 DOI: 10.6028/jres.110.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 08/11/2004] [Indexed: 06/06/2023]
Abstract
A new method of measuring the electron-antineutrino angular correlation coefficient, little "a", from neutron decay-to be performed at the National Institute of Standards and Technology-will require an electron spectrometer that strongly suppresses backscattered electrons. A prototype consisting of six trapezoidal veto detectors arranged around a plastic scintillator has been tested with an electron beam produced by a Van de Graaff accelerator. The results of this test and its implications for the little "a" measurement are discussed.
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Affiliation(s)
- A Komives
- DePauw University, Greencastle, IN 46135
| | | | - C Trull
- Tulane University, New Orleans, LA 70118
| | - F B Bateman
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - M S Dewey
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - A K Thompson
- National Institute of Standards and Technology, Gaithersburg, MD 20899
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